Nutrition Month: Keeping Your Trees Healthy

Trees may be beautiful and constantly depicted in works of art, but keeping your trees picturesque is a science, not an art. There are right and wrong ways to take care of your trees and keep them healthy.


March is National Nutrition Month and it is a great reminder that health care is not just for people; your trees and shrubs need the right nutrition and care, too.


When most people think about tree nutrition, they think of fertilizer. Trees need macronutrients and micronutrients to live and fertilizer ensures they get those nutrients. Primary nutrients such as nitrogen, phosphorus, potassium, sulfur, calcium and magnesium are called macronutrients. Nutrients needed in much smaller amounts (such as iron, manganese, zinc, chlorine, boron, copper, nickel and molybdenum) are calledmicronutrients.

When selecting a fertilizer you will see three numbers - nitrogen, phosphorous and potassium commonly written as N-K-P. A 10-20-10 fertilizer works well with flowering trees and shrubs and for non-flowering woodies, a basic 10-10-10 works well. To lay the fertilizer, punch holes into the ground about 2-3 feet apart and 6-8 inches deep on a grid system covering the area to be fertilized. Divide the total amount of fertilizer needed among the holes and cover each hole with a handful of soil.


Mulch acts as a soil insulator; it provides a buffer from extreme temperatures (a must in Minnesota!), retains water and protects the tree roots from weed competition. Another benefit of mulch is that it protects your trees from your lawn equipment and vise versa. The perimeter around your tree means you won’t accidentally hit your tree with the lawn mower or weed whip.

To maximize the benefits of mulch, you need to properly lay mulch. First, you need to remove the grass in a 3-10 foot area around the tree. Then you need to have a 2 to 4-inch layer of mulch. Finally, make sure the mulch is not touching the trunk of the tree – that will cause mulch to harm, not help, your tree.


As you probably guessed, water is one of the most important tree nutrients – but how much does a tree need? As the saying goes, you can have too much of a good thing and trees can have too much water. Over-watered trees can suffocate them or cause them to be more susceptible to fungal diseases.

Older trees can handle a wider range of water conditions, but a good rule of thumb is to make sure the soil around a tree is moist – not soggy. Sometimes nature takes care of this with a good rain, but if not, a few minutes with a garden hose will do the trick.


If you haven’t started, now is the time to think about pruning your Oak trees. With warmer weather approaching, the deadline for pruning Oak trees may be less than a few weeks away. Once Oak Wilt spores start producing, we suggest that you don’t prune or cut your Oak trees. We are happy to provide more information and help in this area—if you have Oak trees that you’re questioning, give us a call!

And for all your tree and shrub health care, we offer individual and packaged services to help keep you keep your trees beautiful without having to do the work to keep them that way. Contact us for more information and to make the best of your landscape this year.